Innovative energy efficient UV-solution for cross-linking of PSA hot melts

摘要

UV-curing coatings are used more and more often. Not only because they do not contain solvents, which make them environmentally compatible, and because they can be cured very quickly – they are also of very high quality. Demanding applications such as film and food labels, high-performance adhesive tapes and re-sealable food packaging require innovative special adhesives. UV-curable pressure sensitive hot melt adhesives (PSA) are permanently tacky and are used for self-adhesive applications. They are solid at room-temperature, therefore applied at elevated temperatures in the molten stage. Before they develop their characteristic adhesive properties, they have to be cross-linked by UV-irradiation. Commonly used and well known for UV-curing processes are Hg-medium pressure lamps with different dopants. They emit a broadband spectrum from the UV-to the Visible up to the IR-spectral range. As they generate a lot of heat –up to 800-900°C-, they can cause problems especially for temperature sensitive substrates. Their electrical power consumption is in the range of 120-240W/cm.